class Myclass(type):
    def __init__(self,a,b,c):
        # self -->FOO,a-->"FOO",b-->(),c-->{}
        print("元类执行了")
    def __call__(self, *args, **kwargs):
        obj = object.__new__(self) # f1
        self.__init__(obj,*args, **kwargs)
        return obj
class FOO(metaclass=Myclass):
    def __init__(self,name):
        self.name=name

f1=FOO("alex")
print(f1.__dict__)